BOSTON (AP) — State public health officials have issued new guidelines that could lead to more aerial spraying of mosquitoes to prevent the spread of eastern equine encephalitis.

The Massachusetts Department of Public Health said the changes announced on Wednesday come amid indications of increased risk of the disease to humans.

Under the new guidelines, health officials could consider spraying in a region if just one mammal-biting mosquito is found to be infected with EEE. Under the previous guidelines, officials had to determine there was a critical risk, based on at least two human or mammal cases of EEE.

The department will also look at a more targeted approach to aerial spraying, rather than full regional spraying.

There have been nine human cases of EEE reported in Massachusetts since 2006. One death was reported last year.